1. Field of Invention
This invention applies generally to the field of recycling waste material to produce easily harnessed energy sources. The current energy shortage has magnified this need for alternative energy sources. This invention provides a method and apparatus whereby all the waste material from a particular area except metals and certain plastics can be recycled to produce methane gas and other by-products.
The present invention has applications in both commercial and household systems. If a large source of waste material is available such as a garbage dump or a farm, it will be possible with this invention to commercially produce great volumes of methane gas without the addition of any significant amount of energy. In individual household applications this invention can be utilized to process the waste materials from almost all the domestic sources such as human wastes, pet wastes, grass and shrubbery cuttings, discarded food, residue from garbage disposals, and dry paper product trash excluding metals and some plastics. In this manner the particular household could have a source of energy for powering air-conditioning units, heating units, hot water heaters, household electrical appliances, lawn mowers, household automobiles, and other asundry household items. This system would be especially desirable due to the rapidly increasing cost of electricity.
2. Description of the Prior Art
Systems for decomposing waste material utilizing anaerobic and aerobic bacteria are old in the art. Over the years these systems have not been subject to refinements and improvements due to the seemingly unlimited sources of energy such as electricity and fossil fuels. Most prior systems have been backyard systems with relatively little sophistication. However, this invention applies some new principles to the prior systems.
The prior art does disclose the use of electrolysis through the slurry solution to increase the bacterial decomposition of the waste material. An example of such a system is U.S. Pat. No. 3,336,220 issued to G. Neidl on Aug. 15, 1967.
Other examples of the prior art which deals with methane gas production are exemplified in the following U.S. Pat. Nos.:
1,880,772 -- Buswell PA1 2,262,576 -- Durdin PA1 3,640,846 -- Johnson
One problem associated with the prior art was that the oxygen produced by the electrolysis reaction tended to inhibit the growth of the anaerobic bacteria. The present invention overcomes this problem and yet still allows for the use of electrolysis to increase the bacterial growth. Another problem associated with the prior art was the accumulation of unprocessible or processed floating waste materials suspended at the surface of the slurry solution. These relatively inert substances inhibited the production of methane by essentially insulating the slurry solution from the gaseous section of the airtight tank. Accordingly, this invention claims several embodiments for facilitating the removal of these floating waste materials which thereby increases the interface area between the gaseous and liquid materials in each tank.
The prior art utilized various methods of collecting gas and of controlling the level of the slurry in the tanks which were inefficient and cumbersome. This invention encompasses methods and apparatus which increase the efficiency and effectiveness of the gas collecting process.